Sorry for replying so late.I actually wasn't able to find any reference photos of the back of the head. So for this mask, I just made it up. But... After I finished the mask, I found some pictures. So I remade the mask based on the better pictures. You can see what the back of the head should look like, towards the end of this video. https://youtu.be/cU4iWT7LWug

Thanks!

For the eyes I used halfs of 60mm clear plastic Christmas ornaments. To make them Black, I used a sponge to stipple in a little bit of transparent black airbrush paint.